U.S. patent number 4,292,558 [Application Number 06/066,732] was granted by the patent office on 1981-09-29 for support structure for dynamoelectric machine stators spiral pancake winding.
This patent grant is currently assigned to Westinghouse Electric Corp.. Invention is credited to Carl Flick, Sui-Chun Ying.
United States Patent |
4,292,558 |
Flick , et al. |
September 29, 1981 |
Support structure for dynamoelectric machine stators spiral pancake
winding
Abstract
A support structure for unitizing coil turns into a single
member and bracing each coil of a multi-coil stator dynamoelectric
machine. Each stator coil includes several turns relatively
concentrically disposed. Each coil turn constitutes two
longitudinal conductor portions and two end turn conductor
portions. One end turn portion serially connects two longitudinal
portions and the remaining end turn portion serially connects one
of the longitudinal portions with a longitudinal portion of a
concentrically adjacent coil. Each coil preferably lies in a plane
defined by a portion of a cylinder and the coils are disposed in a
cylindrical arrangement having a longitudinal axis therethrough
such that one longitudinal portion of the outermost coil turn lies
along the outer radial extent of the cylindrical arrangement and
the remaining longitudinal portion of the outermost coil turn lies
radially nearer the longitudinal axis of the cylindrical
arrangement. A rigid foundation member is situated in the plane of
each coil within the concentrically innermost turn. Turns of each
coil are structurally connected either directly to the foundation
member or indirectly to the foundation member by being
intermediately joined to a turn already joined to the foundation
member. The concentric turns of each coil are separated by a
predetermined distance through the use of interposed spacer members
situated at desired axial and circumferential locations. Such coils
present a spiral pancake appearance and are cooperatively disposed
in the cylindrical arrangement between radially inner and outer
supporting structures. Appropriately shaped wedges are disposed
between selected coils and internal/external supporting members to
account for the skewed or spiral manner in which each of the coils
is arranged in the substantially cylindrical arrangement. Radial
tie rods extending between the radially internal and external
support members structurally integrate those members so as to
insure structural integrity of the cylindrical arrangement. The
radially external support member is preferably configured to
extract load components from individual coil turns exposed at the
cylindrical arrangement's outer periphery by either having radially
inwardly directed struts extending between adjacent turns or having
notches within which the radially outer conductor turns, when
canted, are receivable.
Inventors: |
Flick; Carl (Pittsburgh,
PA), Ying; Sui-Chun (Monroeville, PA) |
Assignee: |
Westinghouse Electric Corp.
(Pittsburgh, PA)
|
Family
ID: |
22071334 |
Appl.
No.: |
06/066,732 |
Filed: |
August 15, 1979 |
Current U.S.
Class: |
310/194;
310/254.1; 310/179 |
Current CPC
Class: |
H02K
3/47 (20130101); H02K 55/04 (20130101); H02K
3/04 (20130101); Y02E 40/60 (20130101); Y02E
40/625 (20130101) |
Current International
Class: |
H02K
55/04 (20060101); H02K 3/46 (20060101); H02K
3/47 (20060101); H02K 55/00 (20060101); H02K
3/04 (20060101); H02K 001/00 () |
Field of
Search: |
;310/43,45,51,179,180,184,192,193,214,198-208,259,260,270 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Neue Losungswege zum Entwurf groBer Turbogeneratoren bis 2GVA,
60kV, by Von Gerhard Aichholzer, Eingelangt, 9-25-74..
|
Primary Examiner: Budd; Mark O.
Attorney, Agent or Firm: Telfer; G. H.
Claims
What is claimed is:
1. A dynamoelectric machine comprising:
a frame structure; and
a substantially cylindrical stator structure having a longitudinal
axis, said stator structure being supported by said frame, said
stator structure comprising
a plurality of electrical coils, each of which comprise an
electrical conductor formed in a plurality of concentric turns
which are serially electrically connected, said turns in each coil
spiraling outwardly about the longitudinal axis,
rigid foundation means, disposed within the concentrically
innermost turn of each coil, for structurally supporting the turns
of each coil, and comprising a support member lying in a curved
plane which corresponds to the spiral shape of the associated coil,
said member's plane thickness perpendicular to said spiral being
less than or equal to said associated coil's conductor's thickness
perpendicular to said spiral, and
means for structurally connecting said turns of each coil with said
supporting foundation means of each coil including a first
plurality of bands protruding through said support member and in
engagement with said turns, said engagement being on said turn's
remote side relative to said support member, said bands being
disposed at selected axial and circumferential locations.
2. A dynamoelectric machine in claim 1 further comprising:
means for maintaining separation spaces between said turns of each
coil.
3. The dynamoelectric machine in claim 2, said conductor turn
separation means comprising:
a plurality of blocks disposed between adjacent turns at selected
axial and circumferential locations.
4. The dynamoelectric machine in claim 1, said structural
connecting means further comprising:
a second plurality of bands wherein each band provides securing
engagement for two turns, said engagement being on opposite sides
of said engaged turns.
5. A dynamoelectric machine comprising:
a frame structure; and
a substantially cylindrical stator structure having a longitudinal
axis, said stator structure being supported by said frame, said
stator structure comprising
a plurality of electrical coils, each of which comprise an
electrical conductor formed in a plurality of concentric turns
which are serially electrically connected, said turns in each coil
spiraling outwardly about the longitudinal axis,
rigid foundation means disposed within the concentrically innermost
turn of each coil for structurally supporting the turns of each
coil,
means for structurally connecting said turns of each coil with said
supporting foundation means of each coil,
means disposed radially inside said electrical coils for radially
internally supporting said plurality of coils; and
means disposed radially outside said electrical coils for radially
externally supporting said plurality of coils comprising a
plurality of struts supported by said radially external support
means, said struts protruding substantially radially inwardly
between adjacent turns for extracting load components from
individual turns.
6. The dynamoelectric machine in claim 5 further comprising:
intermediate support means for structurally integrating said
radially internal and external support means, said integrating
support means being radially disposed between said internal and
external support means.
7. A dynamoelectric machine comprising:
a frame structure; and
a substantially cylindrical stator structure having a longitudinal
axis, said stator structure being supported by said frame, said
stator structure comprising
a plurality of electrical coils, each of which comprise an
electrical conductor formed in a plurality of concentric turns
which are serially electrically connected, said turns in each coil
spiraling outwardly about the longitudinal axis,
rigid foundation means disposed within the concentrically innermost
turn of each coil for structurally supporting the turns of each
coil,
means for structurally connecting said turns of each coil with said
supporting foundation means of each coil,
means disposed radially inside said electrical coils for radially
internally supporting said plurality of coils; and
means disposed radially outside said electrical coils for radially
externally supporting said plurality of coils comprising wherein
coil turns radially adjacent said external support means are canted
so as to be receivable in notches on said radially adjacent
external support means.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to support structures for dynamoelectric
machine stator coils, and more particularly, to support structures
for spiral pancake stator coils.
2. Description of the Prior Art
Air gap stator windings were developed and adapted for use in a
variety of dynamoelectric machines including generators having a
superconducting field winding. Spiral pancake stator winding
configurations utilize individual coils which spiral outwardly from
a radially inner stator boundary to a radially outer stator
boundary. Such winding configuration has certain advantages and is
particularly effective in providing radial and tangential
securement for each of the electrical coils. Such windings are
illustrated in Austrian Pat. No. 329,670 having an effective date
of May 25, 1976, and U.S. Pat. No. 4,151,433, issued Apr. 24, 1979
in the name of Mr. C. Flick and assigned to the Electric Power
Research Institute. In addition to the relative coil disposition in
the spiral pancake stator winding the latter patent application
illustrates a liquid cooling scheme particularly adapted to such
spiral pancake winding.
Through a series of wedges distributed adjacent the coils and
interposed between radially inner and outer structural members, the
coils, as separate units, were effectively mechanically supported.
Individual coil sides or turns are serially connected and
concentrically arranged to form the coils. Such individual coil
turns are sometimes subjected to continuous vibration in addition
to high electromagnetic forces during fault condition operation.
Exposure of individual coils to such forces necessitate uniform
support for each of the coils as a unit and for each of the coil
turns individually. In section 3 of an article entitled "New
Solutions For The Design Of Large Turbo Generators Up To 2GVA,
60KV" by Aichholzer, Eingelangt, 9-25-74, the following was
included: . . . "the naturally occurring space in the center of
each concentric pancake coil can be partially filled with
ferromagnetic material, which leads to a reduction of the effective
gap and thus to reduced excitation requirements." As stated, the
ferromagnetic material was disposed in the center of each pancake
coil in an unspecified manner so as to reduce excitation
requirements. Forming the coils of a stator winding into a
monolithic structure by injecting impregnating and bonding resins
thereamong has also been suggested for stiffening the coils and
supporting individual conductor turns. While such resins may, under
appropriate circumstances, effectively brace the individual coil
turns, monolithic structures subjected to extended service in
dynamoelectric machines having high mechanical and electromagnetic
force levels have not proven highly successful.
SUMMARY OF THE INVENTION
In accordance with the present invention an improved dynamoelectric
machine is provided in which individual turns of each coil in a
stator winding are structurally integrated with other coil turns of
the same coil to effectively resist local displacement and
vibration thereof induced by mechanical and electromagnetic forces.
The invention generally comprises a frame and a stator structure
supported in the frame with the stator structure including a
plurality of electrical coils each of which has a plurality of
concentric turns, foundation means situated within the
concentrically innermost turn of each coil for structurally
supporting the turns, and means for structurally connecting the
electrical conductor turns of each coil with the supporting
foundation means of each coil. Each coil lies in a plane which
generally spirals outwardly about a longitudinal axis extending
through the stator structure. The foundation means of each coil
preferably comprises a support member lying in a curved plane
corresponding to the spiral shape of the associated coil. The
structural connecting means preferably includes a series of bands
in engagement with the conductor turns and the support member. An
additional series of bands preferably engage two conductor turns on
circumferentially opposite sides of the turns. Means are provided
for maintaining a predetermined separation between adjacent turns
of the same coil. In a preferred embodiment of the present
invention support means are provided for structurally integrating
internal and external support means relative to the interposed
stator coils. Means are also provided for extracting from each coil
turn a component of load transmitted through the coil.
BRIEF DESCRIPTION THE DRAWINGS
The invention will be more fully understood from the following
detailed description of a preferred embodiment, taken in connection
with the accompanying drawings, in which:
FIG. 1 is a transverse sectional view of an exemplary turbine
generator;
FIG. 2 is an axial sectional view of the turbine generator of FIG.
1;
FIG. 3 is a perspective view of the relative disposition of coils
in the turbine generator's stator;
FIG. 4 is a perspective view of a coil illustrated in FIG. 3 and a
support scheme for integrating individual coil turns into a rigid
coil structure;
FIG. 5 illustrates a portion of FIG. 2 and includes means for
radially integrating support structures associated with stator
coils; and
FIGS. 6 and 7 each illustrate a portion of the stator illustrated
in FIG. 2 and exemplify means for transmitting load from individual
coil turns to the radially integrating support structures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is concerned primarily with structurally
integrating individual coil turns of each stator coil in a
dynamoelectric machine so as to reduce internal stresses and local
displacements induced by mechanical vibration and electromagnetic
forces. Accordingly, in the description which follows, the
invention is shown embodied as a large tubine generator.
FIG. 1 illustrates turbine generator 10 which includes rotor 12
which is rotatable about longitudinal axis 14, stator structure 16,
and frame structure 18. Stator structure 16 is disposed about rotor
12 and is structurally connected to frame structure 18 through
radially projecting ribs 20. Stator structure 16 constitutes stator
winding 22, flux shield 24, and internal support tubes 26 and 28.
Although two internal support tubes are illustrated, it is to be
understood that any number may be used will equal facility with the
present invention.
Coolant is transmitted from inlet manifold 30 through suitable
conduits 32 and into water connection headers 34 which are in fluid
communication with internal cooling passages disposed within stator
winding 22. The coolant headers 34 and their relative disposition
within stator structure 16 are best illustrated in FIG. 2.
An expanded axial end view of FIG. 1's stator structure 16 is
illustrated in FIG. 2 and is substantially cylindrical in shape.
Radially internal support tubes 26 and 28 preferably constitute
glass fiber reinforced epoxy such as Micarta material and define a
radially inner boundary for stator winding 22. Flux shield 24
generally includes a plurality of thin plates or laminae which are
approximately 1/50th of an inch in thickness and by example
constitute magnetic material such as silicon iron. Flux shield 24
functions both as a radially external support means for stator
winding 22 and flux constraint for channeling magnetic flux
emanating from a field winding back to the field winding disposed,
in the case of the illustrated generator, on rotor 12. Stator
winding 22 includes a plurality (six in this case) of coils 36
which spiral radially outwardly from the support tubes 26 and 28 to
protective members 38 which preferably constitute laminated glass
fiber reinforced epoxy. Laminate protective members 38 are disposed
radially between coils 36 and flux shield 24 and are secured in
position by longitudinally tapered wedges 40. Protective members
38, which constitute a portion of the radially external support
means, are interposed between coils 36 and flux shield 24 to
protectively buffer the coils and to prevent coil damage by the
flux shield laminations 24 during insertion and assembly of the
coils 36 within the flux shield 24.
Each stator coil 36 has a spiral pancake configuration and
comprises a plurality (illustrated as five) of concentrically
disposed, serially connected coil turns 42 which constitute
interconnected longitudinal and end turn portions. Since the number
of coil turns 42 is primarily related to the voltage in the coils,
it is to be understood that any number of coil turns could be used
(instead of the illustrated five) with the present invention.
Stator winding 22 and its included stator coils 36 are better
illustrated in FIG. 3 which provides an exploded perspective view
thereof. The concentrically innermost turn 42 bounds an opening or
coil window 44. Rigid foundation means is disposed in each coil
window 44 to provide an anchoring structural support for the
conductor turns of each coil 36. Such foundation means preferably
constitute glass fiber reinforced epoxy impregnated laminated
material that may be pressed and cured to the proper contour to
conform to the basic spiral geometry of the coils 36. FIG. 2
illustrates solid foundation means or strongback 46, but ladder
structure strongback 46', as illustrated in FIG. 4, is an
acceptable substitute therefor. Design constraints such as the
magnitude of the electromagnetic forces experienced by the coils
may dictate the percentage of open area 48 of strongback 46'.
Strongbacks 46 and 46' lie in curved planes and have thicknesses
perpendicular to the curved planes not greater than the thickness
of coil turns 42 which lie coplanar therewith.
As shown in FIG. 4, structural connecting means such as bands 50
structurally connect coil turns 42 with strongback 46' at desired
axial and circumferential locations. Bands 50 preferably protrude
through openings 52 formed in strongback 46' and extend to the
circumferentially and axially remote sides (relative to strongback
46') of the longitudinal and end turn portions respectively of the
individual coil turns 42. A second set of structural connecting
bands 50' are disposed so as to structurally connect relatively
inner and outer concentric coil turns 42. Such structural
connection of concentric coil turns 42 to one another is sometimes
necessary to avoid connection interference problems such as spacial
constraints where bands 50 are joined to strongback 46'. In other
words, if each coil turn 42 were directly structurally connected to
strongback 46' then connecting bands 50 may be of such substantial
number as to interfere with each other at their connection with
strongback 46'. Additionally, if the illustrated connecting
technique (openings 52) with strongback 46' were utilized,
strongback 46' could weaken and lose the rigidity necessary to
structurally support the individual coil turns 42.
Separating means such as conformable spacer blocks 53 are disposed
between adjacent coil turns 42 at desired axial and circumferential
locations between longitudinal and end turn portions, respectively,
to maintain predetermined spacial relationships therebetween.
Spacer blocks 53, when used in combination with bands 50 and 50',
enable effective securement and structural integration of the coil
turns 42 into a single coil unit which is highly resistant to
vibration and can be readily supported as an entirety. Spacer
blocks 53 also prevent rubbing between adjacent coil turns 42 and
so avoid damage resulting therefrom.
FIG. 5 is a cut away axial view of a portion of stator 16. Radial
structural integration means such as rods 54 interconnect the
radially internal and external support means for stator winding 22
so as to provide additional rigidity and augment the mechanical
strength of the internal support tubes 26 and 28. Radially disposed
rods 54 extend radially across the illustrated coil window 44.
Strongback 46 and 46' have been removed from FIG. 5 to provide
greater clarity, but it is to be understood that such radial
support rods 54 could protrude through openings in those
strongbacks.
FIGS. 6 and 7 illustrate 60.degree. segments of stator structure 16
and show alternative means for transmitting circumferential load
components from coil turns 42 disposed radially adjacent laminate
protective members 38. The scheme of FIG. 6 for transmitting load
components from individual coil turns 42 includes a plurality of
struts 56 which protrude substantially radially inwardly from the
protective members 38 and pass between adjacent coil turns 42 such
that circumferential forces exerted by and transmitted through
coils 36 are transferred piecemeal through struts 56 to protective
members 38 so as to avoid force accumulation and possible
deformation of individual coil turns 42. The scheme of FIG. 7 for
transmitting load from individual coil turns 42 to protective
members 38 includes notches 58 formed in the radially inner surface
of protective members 38 for receiving canted or angularly
displaced coil turns 42 therein. As can be seen, coil turns 42
which are radially separated from protective members 38 are not
canted so as to minimize the radial size of stator structure
16.
It will now be apparent that an improved dynamoelectric machine
stator structure has been provided in which spiral pancake coils
are securely supported and the individual coil turns thereof are
structurally integrated to form a coil structure of substantial
rigidity. Various configurations utilizing structurally integrated
coils are also provided for preventing circumferential force
accumulation and possible coil turn deformation by individually
transmitting load from the various coil turns. As such, a stiffer
stator winding having high resistance to vibration and
electromagnetic displacement obtains.
* * * * *